Precision power supplies have applications in electronic equipment having narrow tolerance output voltages. It is not uncommon in state of the art electronic equipment to have requirements for output voltage tolerances of less than +/-1%. This disclosure is drawn to the class of such power supplies producing a closely regulated output.
The use of matched resistors as voltage dividers is shown in U.S. Pat. No. 4,161,742 by Cheek et al. This reference shows the use of matched ratio resistors in stepped values combined with a detector for finding cross connections in a wiring harness. The details of fabricating matched resistors in semiconductor devices is discussed in U.S. Pat. No. 4,565,000 by Brokaw. The use of matched resistors for increased accuracy of an A/D converter in U.S. Pat. No. 4,769,628 by Hellerman and in U.S. Pat. No. 5,648,780 by Neidorff.